Skin-stretch Haptic Feedback Augmentation Improves Performance in a Simulated Laparoscopic Palpation Task.

Laparoscopic surgery brings substantial benefits to patients. However, it remains challenging for surgeons because of motion constraints and perception limitations. Notably, the perception of interactions with organs is largely compromised. This paper evaluates the effectiveness of a forearm-based skin-stretch haptic feedback system rendering surgical tool tip force. Twenty novice participants had to discern the stiffness of samples to investigate stiffness perception in a simulated laparoscopic task. The experimental protocol involved manipulating samples with three difficulty levels and testing three feedback conditions: no augmentation, visual feedback, and tactile feedback. The results demonstrate that feedback significantly enhances the success rate of laparoscopic palpation tasks. The proposed tactile feedback boosts confidence and task speed and reduces peak force and perceived workload. These benefits become even more pronounced when difficulty increases. These promising findings affirm the value of skin-stretch haptic feedback augmentation in improving performance for simulated laparoscopy tasks, paving the way for more integrated and deployable devices for the operating room.

Robot-Assisted Bone Cement Injection.

In this article, assistance to bone cement injection is studied, with a focus on vertebroplasty, a procedure dedicated to the treatment of vertebral compression fractures. A robotic system that can remotely be operated at pressures up to 140 bar is presented. It improves cement polymerization control, combining a cold passive exchanger that slows down the cement curing in the syringe and an active exchanger that controls the injected cement temperature. The cement remote injection uses a rate control teleoperation strategy with force feedback to help monitoring the cement state. In addition to laboratory assessments, cadaver experiments were performed to illustrate the satisfactory operation of the whole system.

Cement Plug Fragmentation Following Percutaneous Cementoplasty of the Bony Pelvis: Is it a Frequent Finding in Clinical Practice?

PURPOSE: To report the rate of fragmentation of the cement plug following percutaneous cementoplasty with polymethylmethacrylate (PMMA) in the bony pelvis (i.e., pelvic bones or sacrum). MATERIALS AND METHODS: Post-interventional and follow-up CT scans of 56 patients (36 men; mean age of 68.4 ± 15.4) with a total of 98 percutaneous cementoplasty procedures were analyzed. Indications for treatment included painful malignant tumors (42.9%; 42/98) and insufficiency fractures (57,1%; 56/98). Fragmentation of PMMA was recorded for each cement plug. RESULTS: Mean interval between the procedure and the last available CT scan was 29.3 ± 18.8 months. There was no significant difference between the length of follow-up of malignant lesions (27.6 ± 15.1 months) and insufficiency fractures (29 ± 20.5 months) (p = 0.69). Fragmentation was diagnosed following 2/98 (2%) procedures, both in the malignant lesions group. The time intervals between the procedure and the first visualization of cement fragmentation were 6 for the first and 24 months for the second patient. CONCLUSION: Fragmentation of the PMMA plug following percutaneous cementoplasty in the bony pelvis is a rare finding at midterm follow-up. It was only observed in cementoplasty performed in malignant lesions and seems to be more a consequence of local mechanical stresses than as a result of porosity.

Biomechanics of the Osseous Pelvis and Its Implication for Consolidative Treatments in Interventional Oncology.

The osseous pelvis is a frequent site of metastases. Alteration of bone integrity may lead to pain but also to functional disability and pathological fractures. Percutaneous image-guided minimally invasive procedures, such as cementoplasty and screw fixation, have emerged as a viable option to provide bone reinforcement and fracture fixation, as stand-alone or combined techniques. Understanding the biomechanics of the osseous pelvis is paramount to tailor the treatment to the clinical situation. The purpose of the present review is to present the biomechanics of the osseous pelvis and discuss its implication for the choice of the optimal consolidative treatment.

Subjective Analysis of the Filling of an Acetabular Osteolytic Lesion Following Percutaneous Cementoplasty: Is It Reliable?

PURPOSE: To study the interobserver agreement for the analysis of lesion filling following cementoplasty of an acetabular osteolytic lesion, and investigate how subjective analysis compares to volumetric analysis. MATERIALS AND METHODS: A total of 21 acetabular osteolysis were retrospectively analysed on pre- and immediate post-cementoplasty CT-scans by two senior interventional radiologists and one resident using a 4 grade scale to quantify lesion filling (Fsubjective): F ≤ 25%, 25% < F ≤ 50%, 50% < F ≤ 75% or F > 75%. Volumetric analysis (Fvolumetric) was performed with the delineation of the osteolysis and the cement using regions of interest. The interobserver agreement for Fsubjective was evaluated using the Fleiss' Kappa test for the 4 grade scale and for a simplified 2 grades scale (F ≤ 50% and F > 50%). The performance of Fsubjective versus Fvolumetric (considered as the gold standard) was then evaluated for each reader using the calculation of accuracy and error to reference for the 4 grades scale and accuracy, sensitivity, specificity, positive predictive value and negative predictive value for the 2 grade scale. RESULTS: Interobserver agreement was considered as very low (< 0.2) for the 4 grade scale analysis and as low (> 0.2 and < 0.4) for the 2 grade scales analysis with kappa factors of 0.196 and 0.36 respectively. Compared to volumetric analysis, the overall accuracy of the 4- and 2- grade scales were 36.5% and 60% respectively. CONCLUSION: Subjective evaluation of cement filling of an acetabular osteolytic lesion is associated with poor interobserver agreement and overestimation of the percentage compared to volumetric analysis.

Bone cement modeling for percutaneous vertebroplasty.

Vertebroplasty procedures provide a significant benefit for patients suffering from vertebral fractures. In order to address current issues of vertebroplasty procedures, an injection device able to control the bone cement viscosity has been developed. In addition, this device allows to protect the practitioner by removing him/her from the X-rays area. In this context, a study is first proposed to quantify the bone cement viscosity during its polymerization reaction on a rotational rheometer. These experimental measurements have led to the identification of a complete behavior law that takes into account the simultaneous effects of shear rate, time, and temperature. Based on this preliminary study, this article finally aims to prove the ability of estimating the viscosity of the flowing bone cement on the developed injection system. A final set of experiments validates that the injection device dedicated to vertebroplasty procedures can control the flowing bone cement viscosity by acting on the temperature. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1504-1515, 2019.

Automatic planning of needle placement for robot-assisted percutaneous procedures.

PURPOSE: Percutaneous procedures allow interventional radiologists to perform diagnoses or treatments guided by an imaging device, typically a computed tomography (CT) scanner with a high spatial resolution. To reduce exposure to radiations and improve accuracy, robotic assistance to needle insertion is considered in the case of X-ray guided procedures. We introduce a planning algorithm that computes a needle placement compatible with both the patient's anatomy and the accessibility of the robot within the scanner gantry. METHODS: Our preoperative planning approach is based on inverse kinematics, fast collision detection, and bidirectional rapidly exploring random trees coupled with an efficient strategy of node addition. The algorithm computes the allowed needle entry zones over the patient's skin (accessibility map) from 3D models of the patient's anatomy, the environment (CT, bed), and the robot. The result includes the admissible robot joint path to target the prescribed internal point, through the entry point. A retrospective study was performed on 16 patients datasets in different conditions: without robot (WR) and with the robot on the left or the right side of the bed (RL/RR). RESULTS: We provide an accessibility map ensuring a collision-free path of the robot and allowing for a needle placement compatible with the patient's anatomy. The result is obtained in an average time of about 1 min, even in difficult cases. The accessibility maps of RL and RR covered about a half of the surface of WR map in average, which offers a variety of options to insert the needle with the robot. We also measured the average distance between the needle and major obstacles such as the vessels and found that RL and RR produced needle placements almost as safe as WR. CONCLUSION: The introduced planning method helped us prove that it is possible to use such a "general purpose" redundant manipulator equipped with a dedicated tool to perform percutaneous interventions in cluttered spaces like a CT gantry.

Soft Robots Manufacturing: A Review.

The growing interest in soft robots comes from the new possibilities offered by these systems to cope with problems that cannot be addressed by robots built from rigid bodies. Many innovative solutions have been developed in recent years to design soft components and systems. They all demonstrate how soft robotics development is closely dependent on advanced manufacturing processes. This review aims at giving an insight on the current state of the art in soft robotics manufacturing. It first puts in light the elementary components that can be used to develop soft actuators, whether they use fluids, shape memory alloys, electro-active polymers or stimuli-responsive materials. Other types of elementary components, such as soft smart structures or soft-rigid hybrid systems, are then presented. The second part of this review deals with the manufacturing methods used to build complete soft structures. It includes molding, with possibly reinforcements and inclusions, additive manufacturing, thin-film manufacturing, shape deposition manufacturing, and bonding. The paper conclusions sums up the pros and cons of the presented techniques, and open to developing topics such as design methods for soft robotics and sensing technologies.

Design and development of a robotized system coupled to µCT imaging for intratumoral drug evaluation in a HCC mouse model.

Hepatocellular carcinoma (HCC) is one of the most common cancer related deaths worldwide. One of the main challenges in cancer treatment is drug delivery to target cancer cells specifically. Preclinical evaluation of intratumoral drugs in orthotopic liver cancer mouse models is difficult, as percutaneous injection hardly can be precisely performed manually. In the present study we have characterized a hepatoma model developing a single tumor nodule by implantation of Hep55.1C cells in the liver of syngeneic C57BL/6J mice. Tumor evolution was followed up by µCT imaging, and at the histological and molecular levels. This orthotopic, poorly differentiated mouse HCC model expressing fibrosis, inflammation and cancer markers was used to assess the efficacy of drugs. We took advantage of the high precision of a previously developed robotized system for automated, image-guided intratumoral needle insertion, to administer every week in the tumor of the Hep55.1C mouse model. A significant tumor growth inhibition was observed using our robotized system, whereas manual intraperitoneal administration had no effect, by comparison to untreated control mice.

Design and in vivo evaluation of a robotized needle insertion system for small animals.

The development of imaging devices adapted to small animals has opened the way to image-guided procedures in biomedical research. In this paper, we focus on automated procedures to study the effects of the recurrent administration of substances to the same animal over time. A dedicated system and the associated workflow have been designed to percutaneously position a needle into the abdominal organs of mice. Every step of the procedure has been automated: the camera calibration, the needle access planning, the robotized needle positioning, and the respiratory-gated needle insertion. Specific devices have been developed for the registration, the animal binding under anesthesia, and the skin puncture. Among the presented results, the system accuracy is particularly emphasized, both in vitro using gelose phantoms and in vivo by injecting substances into various abdominal organs. The study shows that robotic assistance could be routinely used in biomedical research laboratories to improve existing procedures, allowing automated accurate treatments and limited animal sacrifices.

Design and evaluation of a robotic system for transcranial magnetic stimulation.

Transcranial magnetic stimulation is a noninvasive brain stimulation technique. It is based on current induction in the brain with a stimulation coil emitting a strong varying magnetic field. Its development is currently limited by the lack of accuracy and repeatability of manual coil positioning. A dedicated robotic system is proposed in this paper. Contrary to previous approaches in the field, a custom design is introduced to maximize the safety of the subject. Furthermore, the control of the force applied by the coil on the subject's head is implemented. The architecture is original and its experimental evaluation demonstrates its interest: the compensation of the head motion is combined with the force control to ensure accuracy and safety during the stimulation.

A patient-mounted robotic platform for CT-scan guided procedures.

In this paper, we present a novel robotic assistant dedicated to medical interventions under computed tomography scan guidance. This compact and lightweight patient-mounted robot is designed so as to fulfill the requirements of most interventional radiology procedures. It is built from an original 5 DOF parallel structure with a semispherical workspace, particularly well suited to CT-scan interventional procedures. The specifications, the design, and the choice of compatible technological solutions are detailed. A preclinical evaluation is presented, with the registration of the robot in the CT-scan.

Online robust model estimation during in vivo needle insertions.

Soft tissue modeling is of key importance in medical robotics and simulation. In the case of percutaneous operations, a fine model of layers transitions and target tissues is required. However, the nature and the variety of these tissues is such that this problem is extremely complex. In this article, we propose a method to estimate the interaction between in vivo tissues and a surgical needle. The online robust estimation of a varying parameters model is achieved during an insertion in standard operating conditions.